Computers use a web connection that includes hardware and software in order to resource share. For example, the accessory devices such as computer hard disc data and printer, etc., have been popular solutions in today's technology market. However, for the user of non-enterprise_systems, especially for the common home computer, this web device is very expensive. Even for a small venture with its own investment or offices, the users can not afford the construction of an entire web. Because of insufficient budget, this sort of customer is in need of common computer devices.
For instance, the printer the most popular computer accessory device is scarce for every computer as each user is matched with a printer respectively, so the requirement for a shared common device is very important in consideration of economic effectiveness. Therefore, the industry is concerned with how to supply cheaper and faster accessory devices.
The prior art's technique is to manipulate a printer's input/output switch by hand and since its operation is manual, it is very inconvenient. It is more convenient to apply the software in the user's host for switching the printer. However, the internal elements of this kind of switching device are very tedious. It must use more controlling chips to reach the purpose of control. For instance, a “2 to 1” switch uses at least two universal serial buses (USBs) and the controlling software programs are very complicated and expensive.
Please refer to FIG. 1, which is an example of a system illustration of a “2 to 1” device according to the prior arts. The hosts AP0 and AP1 of the user side, through the output ports of the terminal of a universal serial bus (USB), may be connected to a sharer 11, which is passed and transferred by a multiplexer 15 to make the host AP1 of the connection side connected to a universal serial bus-hub 12 (USB-HUB). The hub itself has a controlling IC, which is connected to a USB controlling chip 13 and a USB output end 16. Through a device connection port 17, a further connection is made to an external USB accessory device, such as the devices of printer, digital camera, etc. (not shown in the figure), while the host AP0 of non-connecting side is then connected to a USB controlling chip 14.
Device output end 16 may be randomly connected to the external USB device, such as: printer, mouse, or scanner, etc. However, the USB controlling chip must be installed at the computer side and controlled under both the relative driving program defined by the USB controlling chip and the software responsible for switching, so the switching instruction may be directly transferred through the USB controlling chip from the AP0 or AP0 host of the user side to order the multiplexer to switch the computer of the connection side, (e.g., switching the original host AP1 to the host AP0).
Sharer 11 of the “2 to 1” type applies two USB controlling chips and one hub IC and, similarly, a “3 to 1” sharer needs three USB controlling chips and one hub IC and, in the same way, a “N to 1” sharer has to use N pieces of USB controlling chips and one hub IC. Besides, using a greater number of applied parts, its controlling software is also more complicated, and it has a restriction caused by the specifications, such as USB 1.1 being unable to be incompatible with USB 2.0.
In addition to the above shortcomings, the prior sharer also has certain popular problems. For example, when a switching instruction is executed, the original host of the connection end—such as AP1 using the accessory device—must be ordered to be off line, then the host AP0 of the connection end may make a connection order, such that a problem is created for the user. For example, if the user shuts off the host AP1 that is still on line with a printer, then it is impossible for another user of the host AP0 to use the printer commonly, and the user of the host AP0 must restart the host AP1 to make a cutting off order, such that he can then make an on line order from the host AP0. This procedure is more inconvenient than switching by hand.